Mechanism for feeding fibrous elements



Dec. 11, 1962 R. D. LAMBERT MECHANISM FOR FEEDING FIBROUS ELEMENTS 2Sheets- Sheet 1 Filed 001;- 22, 1954 INVENTOR.

@Jer/Qlawzri 71 E E #MMM :Qfizweyi 3,967,855 Patented Dec. 11, 19623,067,855 MECHANISM FOR FEEDING FIBROUS ELEMENTS Robert D. Lambert,Sandpoint, Idaho, assignor to Changewood Corporation, Chicago, 11]., acorporation of Illinois Filed Get. 22, 1954, Ser. No. 464,100

1 Claim. (Cl. 198-76) vention in the copending application resides in apair of wheels having scrabbler blades extending radially from theperiphery thereof for turning movement in opposite directions in spacedrelation over the top flight of an inclined conveyor having a quantityof fiber in excess of that capable of passing beneath the wheels so thatthe excess fibers are displaced rearwardly into a mound in advance ofthe first wheel while quantities of fiber, uniform from the volumetricstandpoint, continue up the conveyor for further processing. In using afeed mechanism of the type described in which the rate of feed is basedupon control by volume, it is important to embody means in which thedensity of the material being advanced to the metering device remainssubstantially uniform, otherwise the weight of fiber being advanced willvary in proportion to density. To achieve these conditions, it isnecessary that the lower stratum of the fibers in the mound be somewhatinsensitive to the variation in height of the mound and, when used incombination with vacuum, to minimize the effect of the height of themound. It is important further to provide for substantially uniform orconstant orientation of the fibers and thus substantially uniform airpermeability of the fibrous mass so that the applied vacuum will havesubstantially identical effect in compressing the strata.

Especially when used for the metering of heavy fibrous elements ofrelatively large dimension, such as are described in the copendingapplications Ser. No. 78,692, filed February 28, 1949, now Patent No.2,655,189, issued October 13, 1953, and Ser. No. 344,089, filed March23, 1953, now iatent No. 2,773,789, and the like, for feeding in themanufacture of molded boards and panels, the bulk density of the mass ishigh so that the height of the mound in advance of a metering Wheel hasmarked effect on the density of the lower stratum with the result thatthe weight of fibrous elements advanced varies to an appreciable degreewith the height of the mound. The use of suction operating through theforaminous belt from the underside offers little relief in the controlof density, and, in fact, tends to interfere with the maintenance ofuniform density since the permeability of the mound to the flow of airis dependent somewhat upon the orientation of the fibers and the mannerin which the suction takes on the mound.

With relatively long fine fluffy fibers, such as cotton and syntheticstaple fibers, which are easily compressive in mass, it is difficult tocontrol the uniformity of discharge from the supply source and it hastherefore been difficult to maintain the height of the mound withinsufficiently narrow limits so as to avoid fluctuations in the density ofthe fiber mass and in the resulting feed rate of the metering device ofthe type described. When the mound is large, its Weight serves tocompress the bottom stratum passing beneath the wheel to a considerablygreater extent than when the mound is small. Since the rate of feed isequal to the product of the cross sectional area of the material passingbeneath the metering wheel, the speed of the conveyor and the averagedensity of the mass of material, variations in the density of anystratum is immediately reflected by corresponding variation in the rateof feed.

The objective in control for feeding fibrous elements at a uniform rateby volumetric control has been achieved in accordance with the practiceof this invention by control of conditions to maintain substantially thesame height of the mound in advance of the wheel by which volume iscontrolled and to provide means for securing the same type and degree oforientation in the fibers in the mound. Both of these conditionsexisting concurrently in the mound of fibrous elements heading into themetering wheel can be made available by constant replacement of fibrouselements forming the base of the mound by constant advancement andreplacement thereof with a fresh supply from an external source fromwhich the fibrous elements are received in a fairly constant stream inhaphazard arrangement so that the elements received will havepractically the same amount of orientation when deposited on theconveyor, while the height of the mound is readily controllable byconstruction.

An object of this invention is to provide an improved method and meansfor feeding fibrous materials quantitatively by weight from bulk storageat a constant, predetermined rate, without appreciable short timefluctuations and it is a related object to provide means for feedingsuch fibers from storage without large fluctuations in the feed rate toa volumetric metering device in substantially uniform quantities andwith a relatively constant degree of fiber orientation to minimizevariations in the height of the mound ahead of the metering device andthereby secure a more accurate and uniform performance of the meteringelements.

Another object is to provide an improved method and means for adjustingand controlling the feeding of dis crete particles of fibrous materialto enable a constant rate of feed for advancement and processing intofibrous structures.

Another obiect is to provide a combined storage and feed mechanism forfibrous materials for metering the fibers at a predetermined rate forfurther processing.

Other objects and advantages of this invention will hereinafter appearand for purposes of illustration, but not of limitation, an embodimentof the invention is shown in the accompanying drawing in which FIGURE 1is a schematic view in sectional elevation of a feed system embodyingfeatures of this invention;

FIGURE 2 is a sectional elevational view of a portion of the deviceshown in FZGURE 1 illustrating the arrangement of parts in the meteringsection in greater detail;

FIGURE 3 is a sectional elevational view corresponding to that of FIGURE2 showing a modification in a metering device embodying features of thisinvention;

FIGURE 4 is a top plan view of the structure shown in FiGURE 3, and

FIGURE 5 is a schematic elevational view showing a still furthermodification.

As shown in the drawing, the feed mechanism embodying features of thisinvention comprises a primary feed section wherein fibrous elements arestored and which embodies means for advancing compressive fibrousmaterials at a relatively uniform controlled rate to a sec ondary feedsection in the form of a metering device which operates by control ofvolume for advancing the fibrous elements at a uniform rate for furtherprocessing into fibrous structures. The primary feed section comprises ahousing 10 having an inlet 11 at one end through which fibers areintroduced without regard as to control for quantity or rate but it ispreferred to maintain the volume of fibers in the housing or binsubstantially to fill the housing or at least a part thereof.

The bottom wall of the housing upon which the compressive material restsconstitutes a conveyor in the form of an endless belt 12 movable in onedirection over a rigid flooring 13 for support and which is actuated formovement in the one direction by means of a driving motor 14 connectedby belts 15 and 16 to driving sprockets 17 with a gear box 18 in betweenfor speed control. It is preferred to incline the side walls 19 of thehousing outwardly and downwardly so as to provide for increasing crosssectional area toward the bottom wall to minimize the likelihood ofinterference with the natural flow of fibers by gravitational force torest upon the conveyor 12 forming the bottom wall.

The wall defining the other end of the housing towards which theconveyor advances comprises a vertical conveyor 20 in the form of anendless bucket and/or rake type elevator 21, which operates about anidler sprocket 22 located in a boot below the level of the floor 13 andjust beyond the end of the conveyor 12 and another driving sprocket 24which is operatively connected by a belt or chain 25 to a driving motor26. The flight of the buckets and/or rakes 27 may be deflected inwardlybeyond the upper sprocket as by means of an idler 28 to givesubstantially complete delivery of fibrous elements carried by theconveyor parts or if desired, in place of idler 28 or in additionthereto, brushing means, such as a rotary rake or brush wheel 29 may beemployed to insure such delivery, as illustrated in FIGURE 5 of thedrawing.

In position to receive the elements discharged from the buckets and/orrakes may be a collector chute 31 for conveying the fibersgravitationally upon delivery from the buckets and/or rakes to the topflight of a metering trough in the form of a horizontally disposedendless belt 32 which operates between sprockets 33 and 34, one of whichis driven by means of a motor 35 interconnected by belts 36 and 37 andhaving a gear box 38 in between for speed control. The upper flight ofthe metering belt is supported upon a rigid bottom plate 39 and isconfined between side walls 40 which form a continuous trough to preventinadvertent displacement of fibers advanced in feeding relation beyondthe wheel for further processing and which are contoured in advance ofthe metering wheel to control the height of the mound.

The metering wheel comprises a cylindrical drum 41 operatively connectedto a driving motor 63 by a belt 64 for rotational movement. The wheel ismounted between journals 42 fixed to the forward ends of elongate arms43 for rotational movement about a horizontal axis which issubstantially parallel to the conveyor belt. As illustrated, therotational movements of the wheel and the belt 32 result in opposedmovement of the pins and the upper flight of the belt 32 at their pointof nearest adjacency for movement. The rearward ends of the shaftsupporting arms 43 are pivoted on pins 44 fixed to brackets 45 on asupporting plate 46 for rocking movement to raise or lower the drumrespectively to increase or decrease the spaced relation between theupper flight of the metering belt for control of the height of thestratum of fibrous elements permitted to pass thereunder. Various meansmay be employed for rocking the arms 43 to vary the spaced relationbetween the metering wheel and the conveyor. One such means illustratedschematically in FIGURE 2 comprises a screw 47 which is threadablyengaged intermediate its ends by a nut 48 pivoted on one of the arms 43.One end of the screw is provided with a turning wheel 49 while the otherend is journalled in a bearing to permit free rotational movement toraise and lower the arms.

The metering wheel 41 is formed with a plurality of pins or spikesextending outwardly from the periphery of the cylinder preferablyarranged in rows for operative engagement to displace material engagedthereby backwardly upon the metering belt during operation. In order toachieve greater uniformity in the volumetric ratio of fibrous elementspermitted to pass forwardly beneath the metering wheel, it may bepreferred to provide a suction beneath the portion of the conveyor 32underlying the metering wheel 41. For this purpose the flooring 39supporting the conveyor belt 32 may be formed with an opening incommunication with a suction box 60 joined by a conduit 61 to suitablemeans for withdrawing substantially uniform volumes of air and the belt32 made foraminous.

The side walls 40 forming the trough immediately in advance of themetering wheel are dimensioned for a height which controls the level ofthe mound of the fibers maintained on the belt for advancement intocontacting relation with the metering wheel. Fibrous elements in excessof that capable of being retained in the mound fall over the sides intoa chute 52 which leads back into the boot 23 that is swept by thebuckets and/or rakes of the elevator by turning about the rollersprocket thereby to return the fibrous elements to the bin 11 forrecycling.

Other elements in the feed mechanism embodying features of thisinvention will be described in connection Wtih the operation of thedevice for feeding compressive masses of materials uniformly at apredetermined rate for further processing in the manufacture of fibrousstructures.

Upon operation of belt 12 of the primary feed section, the fibrouselements contained within the bin are conveyed uniformly horizontally inthe direction towards the bucket or rake elevator 20. As the buckets andrakes of the elevator pass upwardly, the portion of the fibers formingthe wall portion in contact with the conveyor will be continuouslydisplaced upwardly by the buckets and/or rakes. The fibers incapable ofcontinuing to be carried upwardly with the conveyor belts upon emergenceof the pile of fibers in surface contact with the elevator will fallback onto the pile towards the rear of the bin while the remainder whichis retained by the buckets and/or rakes will be conveyed by the elevatorfor subsequent deposition onto the metering belt 32.

For proper operating conditions wherein fibrous elements arerecirculated within the bin and to fill the buckets and/or rakesuniformly with elements for conveying to the metering belt, it isdesirable to maintain the amount of fibers stacked up against the beltto provide a pile which terminates prior to reaching the upper sprocket24. For this purpose, means such as a photoelectric cell 53 or switch isprovided at the desired level in the bin for operating the speed controlto increase the linear speed of the conveyor 12 when the level offibrous material falls below the switch 53 and to decrease the linearspeed of the conveyor when the mound of fibers rises to a level abovethe switch. The feed section may be operated successfully when the levelof fibers falls below the switch so long as sufficient fibers remain incontact with the end wall of the conveyor substantially completely tofill the buckets and/or rakes on the elevator. A brush wheel '70 may bepositioned to remove excess fibrous material above a certain level fromthe rakes to insure uniformity in the amount of fiber carried fordelivery when the fibers are long and fluffy.

This refinement in the control for the linear speed of the conveyor belt12 is not essential but it is desirable since it permits variation inspeed to supply sufficient material even when the bin is nearly empty tofill the flights of the elevator and to reduce the speed so as to avoidunnecessary churning of the fibrous materials contained within the bin.

Elevator conveyor 26 is adapted to be driven at a speed sufficient toelevate a quantity of fibrous material slightly in excess of thatcapable of continuously passing upon the flight of the conveyor beneaththe metering wheel of the second feed section so that an excess offibrous elements will be contained in the mound for constant recyclingdown the chute 52 for return to the bin through the boot 23. The excessmaterial delivered by the bucket elevator is brushed back by the pins 50of the metering cylinder 41 to form the mound 54. When this moundreaches a fixed height, the excess fibrous elements fall over thelowered sides 51 into the chute 52 to be returned to the boot 23 aspreviously described. The size of the mound 54 is controlled chiefiy bythe height of the side walls 4 3 and the brushing action of the meteringwheel 41 and is, therefore, relatively independent of the quantity ofmaterials delivered by the elevator conveyor or the quantity of materialwithin the bin.

Regulation of the quantity of fibrous material delivered for furtherprocessing may be made either by adjusting the height of the meteringwheel by means of screw 47 or else by altering the speed of the belt 32by means of the variable speed gear box 38.

When applying this invention to the metering of soft, fluify finematerials such as cotton and the like which are not free flowing, it isusually desirable to make belt 32 foraminous and to apply a constantdegree of vacuum beneath the mound and metering wheel, as showndiagrammatically in FIGURE 3. in this figure, the belt 32 is foraminousand a suction is applied to the underside of its top run by means ofsuction box 29 connected to an exhaust fan (not shown) by pipe 61. Inthis example, the fibrous material to be metered is dropped or brushedonto a belt 32 ahead of metering or spike covered drums 62 similar inconstruction and direction of rotation to the metering wheel 41, butmounted obliquely across the belt. While the material is held againstthe belt by the suction applied to box 60, the drum 62 sweeps any excessmaterial delivered by the elevator 21, or any excess material brushedback by the metering wheel 41, down chute 52 and back to the bin or usemay be made of wheel '71 which has the pins thereon rotating in adirection opposite to the movement of the upper flight of the belt atthe point of nearest adjacency of the belt and the pins to displacefibrous elements above a predetermined level into the mouth of a suctiontube 72 by which the displaced fibers are returned to the bin 11. Thebrushing drum may be driven from the same or a separate motor 63 as usedto drive wheel 41 and is driven in the same direction. If desired theremay be two such drums, mounted chevron fashion as seen in FIGURE 4, soas to more easily cause the excess material in the mound 54 to be pushedover and down both chutes 52.

A number of modifications may be made to the apparatus disclosed in thisinvention without departing from the spirit or scope. For example, theexcess material from the mound 54 may be conveyed back to the bin orelsewhere by a pneumatic tube conveyor, such as 72, which wouldeliminate the need for chutes 52 and the depressions 51 in the sidewalls. The inlet to the pneumatic conveyor would then be situated acrossthe metering belt at the desired level of the top of the mound 54. Alsothe spike covered drum may be replaced by an endless belt carryingsuitable rakes or spikes projecting from its surface.

By way of further modification, a second spiked drum 41 located over anextension of suction box 60, or a separate suction box, may be providedin addition to the spiked drum 41 in FIGURE 4 but spaced a shortdistance rearwardly thereof with a pneumatic tube such as tube 72 incommunication with the upper peripheral portion thereof. By duplicatingthe metering means in series as described, an added degree of precisionwill be achievevd particularly with compressive fibrous materials, sincethe time interval between the two metering devices will give the webtime to spring back and permit any local excess by virtue of the samesection being overcompressed by the first drum or from other causes tobe removed.

Having thus described the nature of this invention by which compressiblefibrous materials may be metered and fed by a volumetric meter with adegree of uniformity that has not, as far as is known, been hithertoachieved, 1 claim:

Apparatus for continuously feeding compressible fibrous material at aconstant and predetermined rate comprising the combination of a primaryfeed section and a secondary feed section, the primary feed sectioncomprising a housing, a horizontally disposed conveyor forming thebottom wall or" the housing mounted for movement in one direction, avertical conveyor forming the end wall of the housing in the directiontowards which the bottom wall travels, means for controlling the linearspeed of the conveyor forming the bottom wall of the housing to displacefibrous material against the conveyor forming the end wall in amountsuflicient to meet the demands thereof, the secondary feed sectioncomprising a trough having a horizontally disposed conveyor forming thebottom wall thereof, a drum mounted for rotational movement about anaxis parallel to the conveyor belt and in spaced relation with the topsurface of the conveyor thereof to define a cross-sectional areatherebetween of predetermined dimension, means on the periphery of thedrum for positive displacement of materials from the conveyor belt inexcess of that for filling the area therebetween, means for controllingthe linear speed of the conveyor forming the end wall of the housing inthe primary feed section for advancing fibrous material onto theconveyor belt of the secondary feed section in advance of the drum inexcess of the amount capable of passing on the conveyor beyond the drumwhereby a mound of fibrous material is formed in advance of the drumwhich is controlled in height and contour by the height of the sidewalls of the trough and by gravity causing the material over and abovethat required for said excess to fall over the side walls of the trough,and means for returning the material so removed to the primary feedsection.

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